Method and apparatus for texturizing synthetic thermoplastic yarns



F. M NAB, JR METHOD AND APPARATUS FOR TEXTURIZING SYNTHETIC THERMOPLASTIC YARNS Filed Oct. 8, 1965 April 22, 1969 3,439,392

INVENTOR.

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United States Patent Office 3,439,392 Patented Apr. 22, 1969 3,439,392 METHOD AND APPARATUS FOR TEXTURIZING SYNTHETIC THERMOPLASTIC YARNS Robert Francis McNab, JrL, Greensboro, N.C., assignor to J. P. Stevens & Co., Inc., New York, N.Y., a corporation of Delaware Filed Oct. 8, 1965, Ser. No. 494,068 Int. Cl. D02g 3/00; B22b 31/02 US. Cl. 28-1 Claims ABSTRACT OF THE DISCLOSURE The disclosure deals with apparatus and process for texturizing synthetic thermoplastic yarns by subjecting the yarns to mechanical vibration in the ultrasonic range and thereby stabilizing or setting the yarns after they have been twisted, crimped or the like. Means are provided for varying the pressure on said yarns so as to impart sufficient vibration to the yarns in order to alter substantially the physical state of said yarns and to impart specific substantially permanent crimp configuration thereto.

This invention relates to the treatment of yarn and a process and apparatus for carrying out such treatment. More particularly, the invention relates to the treatment of synthetic thermoplastic yarn.

It is often desirable to impart to synthetic thermoplastic yarn a specific physical configuration. When a yarn has undergone processing such as twisting, crimping, curling or the like, stresses are created therein and these stresses tend to return the yarn to its previous state. In order to prevent the return of the yarn to its previous state, it may be heat treated or heat set by the application of external heat to relieve the stresses in the yarn. However, heat treating often results in damage to the yarn in addition to other disadvantages. For example, heat treatment may cause greater than desired disturbance of the molecular orientation, alteration of the yarn surface and/ or a change in the hand, as well as affecting other physical and chemical properties. This is especially true when the heat treatment is employed to stabilize the yarn in a specific physical configuration such as crimps, loops, curls, and the like. Accordingly, there exists a need for a process and apparatus which can be utilized to treat synthetic thermoplastic yarns and to impart thereto specific configuration such as crirnps, loops, curls and the like without deleteriously affecting the chemical and physical properties of the treated yarns.

The present invention provides a process and apparatus which obviate the above disadvantages and result in the production of synthetic thermoplastic yarns which exhibit substantially permanently stable physical configuration without the use of heat.

In accordance with the invention, there is provided a process, as well as apparatus, for treating synthetic thermoplastic yarn comprising introducing the yarn into a treatment zone, mechanically vibrating the yarn, pref' erably under pressure, in the treatment zone to impart specific substantially permanent configuration thereto, and removing the yarn from the treatment zone.

The term yarn as employed throughout this specification and in the appended claims is to be understood to include monofilament and multifilament yarns, fibers, rods, and the like in either filamentary, Woven, nonwoven or knitted condition. Moreover, the yarns utilized include synthetic thermoplastic yarns such as the polyamides popularly known as nylons, polyester yarns, acrylic yarns, and olefinic hydrocarbon yarns such as the polypropylenes, the polyethylenes and the like, as well as other synthetic yarns which when subjected to the process and apparatus of this invention acquire a specific substantially permanent physical configuration. Synthetic thermoplastic yarns which may be utilized in carrying out the practice of the invention can be employed in blends with each other in all proportions or in blends with nonthermoplastic synthetic yarns and/or naturally occurring yarns such as wool, cellulosic yarns such as cotton, and modified cellulosic yarns and others. However, in those cases where blends are being processed in accordance with the invention, the percentage of synthetic thermoplastic yarn to nonthermoplastic yarn must be high enough to produce the desired effect.

As mentioned hereinbefore, the yarn to be treated, first brought to the physical state desired, such as blending, twisting, or the like, is introduced into a suitable treatment zone and subjected to mechanical vibration under pressure before being removed from the treatment zone for collection. Mechanical vibration of the yarn is generally achieved by passing the yarn between two surfaces at least one of which is subjected to vibrations as set forth more fully hereinafter. In order to impart the required amount of vibration to the yarn being treated, it is subjected to a widely varying degree of pressure. Initially, the treatment zone is subjected to a specific ambient pressure. Subsequently, when the tool of the apparatus (described in detail below) is carried forward by. the transducer, the pressure is increased as determined by the amplitude of the power input to the transducer. As. thetransducer retreats, the pressure decreases. However, the yarn is subjected to at least. enough pressure in the treatment Zone to cause it to change its physical structure. Generally the maximum amount of pressure is dictated by the number of filaments, thickness, and other characteristics of the yarn. Excessive pressure will flatten or cut the yarn, or otherwise damage it. The particular amount of pressure necessary for a particular yarn or blend of yarns being processed is readily determinable.

The mechanical vibrations applied to a yarn being processed should at least be sufficient to bring about a change in physical structure of the yarn. The rate of vibration is determined by the frequency of the input to the transducer of the hereinafter described apparatus. Theoretically, the range of frequency used. is unlimited. The practical lower frequency limit is determined by production requirements, since the actual work done decreases as the frequency decreases. A high rate of production through a short treatment zone results in intermittent treatment if the frequency is low enough. The rate of vibration is limited only by available apparatus. Since the dimensions of the transducer tool are determined by wave length, high frequency equipment can be made much smaller. This greatly increases the number of pieces of production equipment to which the process and apparatus can be applied. The particular frequency rate for a particular yarn or blend of yarns being processed is readily determinable. Very good results have been attained, however, in a range of about 20,000 cycles per second on polyester yarns (Dacron (a polyester formed by the reaction of ethylene glycol with terephthalic acid) type 56, semidull finish) of 40 denier and 27 filaments with an anvil and tool which were subjected to pressure of up to a maximum of about pounds per square inch. The yarn was passed through three linear inches of treatment zone at the rate of about 15 feet per minute.

Yarn being treated may be introduced into the treatment zone at widely varying rates of speed However, the speed of the yarn into the treatment zone should at least be slow enough so that the effects of vibration under pressure can be imparted thereto. The particular speed most suitable with a particular type of yarn is readily determinable.

In carrying out the process of the instant invention, the rates of vibration, pressure and speed of introduction of the yarn into the treatment zone are dependent upon each other. Generally as the rate of vibration and pressure is increased, the speed at which the yarn is introduced into the treatment zone is increased. On the other hand, in those cases where the vibratory rate being employed is relatively low, the speed of introduction of the yarn into the treatment zone is decreased in order to give the yarn sufficient residence time in the treatment zone for the vibrations to take effect. It is to be noted, however, that the pressure on the yarn should never exceed an amount greater than that at which the yarn tends to undergo changes in diameter along its longitudinal axis where only crimping, curling, or the like is to be achieved. On the other hand, fusion of the yarn being treated can be accomplished, if desirable, by raising the pressure and rate of vibration. In such a case, where only a single yarn is being processed, the fibers thereof are fused together. If more than one yarn or a fabric is being processed, the yarns can be fused with each other to form a sheet or film depending upon the number of yarns used. A portion of a fabric composed of thermoplastic synthetic yarns, as for example, its edge, may be fed through the treatment zone at sufficient pressure to fuse the thermoplastic synthetic yarns to form a selvedge.

Although the instant invention is carried out by introducing the yarn into and collecting it from the treatment zone at widely varied rates of speed, it is also possible to introduce the yarn intermittently into the treatment zone while at the same time intermittently vibrating the yarn, preferably under pressure, and intermittently removing it from the treatment zone as opposed to continuous introduction, vibration and collection. In another variation of the invention, the yarn is continuously introduced into the treatment zone and intermittently vibrated therein, preferably under pressure, while continuously being taken up for collection.

Regardless of the particular sequence of process steps employed, the yarn being treated is subjected to force and internal friction by direct application of mechanical energy which alters the physical state thereof and imparts specific physical configuration thereto which is substantially permanent in nature, When such treated yarns are subsequently formed into fabric with untreated yarns, they exhibit unusual effects, thereby resulting in the formation of a novelty fabric.

Reference is directed to the attached drawing illustrating the apparatus of the invention wherein:

FIG. 1 is an elevational view of the apparatus.

As shown, apparatus in accordance with the invention generally comprises means for applying pressure to a yarn and means for mechanically vibrating the yarn, both means being located opposite each other and having opposing surfaces to engage the yarn therebetween.

More specifically, the apparatus comprises a fixed support 11 having a threaded supporting member 12 afiixed thereto. A sleeve 13, separated into two sections by a panel 14, is adapted to be threadably engaged at one end with support member 12. At the opposite end of the sleeve and disposed therein is an anvil 15 having a flat or planar surface for engagement with the yarn as set forth more fully hereinafter. A spring 16, located in the sleeve, rides against dividing panel 14 and the base of the anvil 15. A locking nut 17 serves to lock the sleeve in position on the support member 12.

A second support 18 located opposite the fixed support 11 has attached thereto transducer 19. The horn or moving member of transducer 19 is shown at 20. The terminal portion or tool which has a flat or planar surface is detachable for replacement, and is shown at 21. The transducer is fixed to support 18 through stationary shaft 22. The transducer may be magnetostrictive and supplied by a suitable source of electric current (not shown) or piezoelectric and connected to a suitable voltage source (not shown) where the transducer 19 is spring-loaded or pneumatically loaded to provide pressure.

As shown in FIG. 1, a yarn 24 is passed between the surfaces of the anvil 15 and the tool 21 after being fed from a reel or other suitable continuous feed mechanism (not shown) and passing over continuous feed drum 25. Any suitable continuous feed mechanism can be employed and it may be operated in a continuous or semi-continuous, that is, intermittent manner. As the yarn leaves the area between the anvil and tool, it passes over drawing drum 26 and is collected on a suitable collecting means (not shown).

The apparatus of this invention being of relatively simple design is attached with facility to any suitable piece of yarn processing equipment such as, for example, a spinning frame, yarn twister, superloft machinery, yarn winding apparatus, quillers, and others. Utilization of the apparatus in accordance with the process of the invention releases substantially no heat to the surrounding atmosphere and consequently there is no need for heat removal apparatus or air cooling apparatus, such as refrigeration or the like. Furthermore, changing air currents and ambient temperature changes have no noticeable effect on the operation of the apparatus. Accordingly, input adjustments are held to a minimum.

In operation, the process is carried out on the apparatus by initially applying the desired degree of pressure to the anvil 15 and the tool 21. This is accomplished simply by adjusting the sleeve 13 so that the surfaces of the anvil 15 and tool 21 rest against each other under the desired amount of pressure. Next, the yarn is fed over the continuous feed drum 25 between the surfaces of the tool and anvil and over the drawing drum 26, and thence to a collection device. Subsequently the transducer is energized by gradually increasing the input until the desired results are obtained. If necessary, the rate of travel of the yarn can be raised or lowered to the optimum speed of introduction at the particular rate of vibration and amount of pressure being employed. Inspection of the product will indicate whether the desired results are being achieved.

In those cases where it is desired to fuse the yarn and to convert it into a sheet or film, operation of the apparatus takes place at relatively high power inputs and high pressures which cause yarn being treated to achieve approximately a molten state, although substantially no heat is given off and the process is carried out at atmospheric pressure, even though pressure is applied to the yarn as it passes between the surfaces of the tool and anvil.

I claim:

1. A process for crimping synthetic thermoplastic yarn comprising introducing said yarn into a treatment zone having opposing surfaces mechanically vibrating said yarn between said surfaces varying the pressure on at least one of said surfaces so as to impart sufiicient vibration to said yarn in order to alter substantially the physical state of said yarn and to impart specific substantially permanent crimped configuration thereto and removing said yarn from said treatment zone.

2. The process as defined in claim 1 wherein the yarn is intermittently introduced into the treatment zone, intermittently mechanically vibrated under pressure in said treatment zone, and intermittently removed from said treatment zone.

3. The process as defined in claim 1 wherein the yarn is continuously introduced into the treatment zone, intermittently mechanically vibrated under pressure in said treatment zone, and continuously removed from said treatment zone.

4. The process as defined in claim 1 wherein the synthetic thermoplastic yarn comprises polyamide yarn.

5. The process as defined in claim 1 wherein the synthetic thermoplastic yarn comprises polyester yarn.

6. The process as defined in claim 1 wherein a synthetic thermoplastic yarn comprises acrylic yarn.

7. The process as defined in claim 1 wherein the synthetic thermoplastic yarn comprises polypropylene yarn.

8. The process as defined in claim 1 wherein the yarn is twisted before introduction into said treatment zone and the twist is substantially permanently set therein in said treatment zone.

9. Apparatus for treating synthetic thermoplastic yarn comprising a first support, means located on said support including an anvil, a second support located opposite the first support, means located on said second support including a tool, said anvil and said tool having planar surfaces opposed to each other for applying pressure to yarn and for mechanically vibrating yarn passed between said surfaces, and continuous feed mechanism to deliver yarn between said surfaces.

10. Apparatus for treating synthetic thermoplastic yarn comprising a first support, a threaded screw disposed on said support, a sleeve divided into two sections, one of said sections having a spring and an anvil located therein, said spring applying force to said anvil, the second section being threaded to cooperate with said threaded screw to adjustably move said sleeve, said force applying spring and said anvil, a second support located opposite the first support, a transducer attached to said second support, a tool operatively connected to said transducer, said transducer mechanically vibrating said tool, said anvil and the head of said tool having surfaces opposed to each other for applying pressure to yarn and for mechanically vibrating yarn passed between said surfaces.

References Cited UNITED STATES PATENTS 3,304,593 2/ 1967 Burklund. 2,938,258 5/1960 Starkie. 3,184,354 5/1965 Strother 156-73 3,211,159 10/1965 Goble.

PHILIP DIER, Primary Examiner.

US. Cl. X.R. 

